(E)-2-[4-(Diethyl­amino)­styr­yl]-1-methyl­pyridinium 4-meth­oxy­benzene­sulfonate monohydrate

In the cation of the title compound, C₁₈H₂₃N₂⁺·C₇H₇O₄S⁻·H₂O, one ethyl group of the diethyl­amino unit is disordered over two sets of sites in a 0.665 (6):0.335 (6) ratio. The styrylpyridinium unit is nearly planar, with a dihedral angle between the pyridinium and benzene rings of 4.27 (8)°. In the crystal, the anion ring is almost perpendicular to the aromatic rings of the cation; the sulfonate-substituted benzene ring forms dihedral angles of 89.60 (8) and 89.37 (8)°, respectively, with the pyridinium and benzene rings of the cation. In the crystal, the three components are linked into a three-dimensional network by O—H...O and C—H...O hydrogen bonds. π–π inter­actions with centroid–centroid distances of 3.6999 (9) and 3.7106 (9) Å are also present.